The Role of the Environment in Overweight and Eating Behavior Variability: Insights from a Multivariate Twin Study

Common genetic factors for uncontrolled eating mechanisms

OBJECTIVE

Reward-based eating drives are putative mechanisms of uncontrolled eating implicated in obesity and disordered eating (e.g., binge eating). Uncovering the genetic and environmental contributions to reward-related eating, and their genetic correlation with BMI, could shed light on key mechanisms underlying eating and weight-related disorders.

METHOD

We conducted a classical twin study to examine how much variance in uncontrolled eating phenotypes and body mass index (BMI) was explained by genetic factors, and the extent that these phenotypes shared common genetic factors. 353 monozygotic twins and 128 dizygotic twins completed the Reward-based Eating Drive 13 scale, which measures three distinct uncontrolled eating phenotypes (loss of control over eating, preoccupation with thoughts about food, and lack of satiety), and a demographic questionnaire which included height and weight for BMI calculation. We estimated additive genetic (A), common environmental (C), and unique environmental (E) factors for each phenotype, as well as their genetic correlations, with a multivariate ACE model. A common pathway model also estimated whether genetic variance in the uncontrolled eating phenotypes was better explained by a common latent uncontrolled eating factor.

RESULTS

There were moderate genetic correlations between uncontrolled eating phenotypes and BMI (.26-.41). Variance from the uncontrolled eating phenotypes was also best explained by a common latent uncontrolled eating factor that was explained by additive genetic factors (52%).

DISCUSSION

These results suggest that uncontrolled eating phenotypes are heritable traits that also share genetic variance with BMI. This has implications for understanding the cognitive mechanisms that underpin obesity and disordered eating.

PUBLIC SIGNIFICANCE

Our study clarifies the degree to which uncontrolled eating phenotypes and BMI are influenced by shared genetics and shows that vulnerability to uncontrolled eating traits is impacted by common genetic factors.

The moderating role of eating behaviour traits in the association between exposure to hot food takeaway outlets and body fatness

BACKGROUND

Previous studies demonstrated a relation between takeaway outlet exposure and health outcomes. Individual characteristics, such as eating behaviour traits, could make some people more susceptible to the influence of the food environment. Few studies have investigated this topic. We aimed to investigate the moderating role of eating behaviour traits (cognitive restraint, uncontrolled eating and emotional eating) in the association between neighbourhood exposure to hot food takeaway outlets (hereafter referred to as takeaway outlets), and takeaway food consumption and adiposity.

METHODS

We used cross-sectional data from a cohort in Cambridgeshire, UK (The Fenland study). Takeaway outlet exposure was derived using participants' residential address and data from local authorities and divided into quarters. The Three Factor Eating questionnaire (TFEQ-R18) was used to measure eating behaviour traits. Primary outcomes were consumption of takeaway-like foods (derived from food frequency questionnaire), and body fat percentage (measured using dual-energy X-ray absorptiometry).

RESULTS

Mean age of participants (n = 4791) was 51.0 (SD = 7.2) and 53.9% were female. Higher exposure to takeaway outlets in the neighbourhood and higher eating behaviour trait scores were independently associated with greater takeaway consumption and body fat percentage. Uncontrolled eating did not moderate the associations between takeaway outlet exposure and takeaway consumption or body fat percentage. The association between takeaway outlet exposure and takeaway consumption was slightly stronger in those with higher cognitive restraint scores, and the association between takeaway outlet exposure and body fat percentage was slightly stronger in those with lower emotional eating scores.

CONCLUSION

Eating behaviour traits and exposure to takeaway outlets were associated with greater takeaway consumption and body fat, but evidence that individuals with certain traits are more susceptible to takeaway outlets was weak. The findings indicate that interventions at both the individual and environmental levels are needed to comprehensively address unhealthy diets.

TRIAL REGISTRY

ISRCTN72077169.

Beyond emotion: online takeaway food consumption is associated with emotional overeating among Chinese college students

BACKGROUND

Online takeaway food has become very popular in China. However, the potential effects of online takeaway food consumption on eating behaviours among individuals during the transition stage from adolescence to young adulthood have not yet been assessed.

OBJECTIVE

This study aimed to examine the effects of takeaway food consumption on emotional overeating behaviour among college students.

METHODS

Data were collected from 1450 college students from six universities in Anhui, China. The frequency of emotional overeating during the past 4 weeks was assessed by the emotional overeating questionnaire (EOQ). Data on the frequency of online takeaway food consumption and other potential risk factors at the individual, interpersonal, physical environment, and macro-system levels were assessed by questionnaire. Multilevel linear regression analyses were employed to explore the association between takeaway food consumption and emotional overeating behaviour.

RESULTS

Compared to those who consumed online takeaway food less than 1 day per week, participants who consumed this food 4-5 days per week and participants who consumed this food 6-7 days per week had significantly higher EOQ scores (β = 0.14, p < 0.05 and β = 0.67, p < 0.001, respectively). More frequent consumption was associated with higher EOQ scores (p for trend < 0.001).

CONCLUSION

A higher frequency of takeaway food consumption was associated with an elevated risk of emotional overeating among college students independent of personal emotional status and other potential confounders at the interpersonal, physical environmental and macro-system levels.

LEVEL OF EVIDENCE

Level V; cross-sectional descriptive study.